1. Field of the Invention
The present invention relates to a signal level decision device and method, especially to a signal level decision device and method capable of reducing the level transition quantity of a signal.
2. Description of Related Art
An electronic product will produce electromagnetic radiations during operation, and may interfere with the normal operation of other devices around it or be harmful to a human body. Therefore, most countries set regulations on the electromagnetic radiation of electronic products to prevent the electromagnetic interference (EMI) from bringing damage. In some fields, the regulations on EMI are extremely strict. For instance, to an automobile network communication device, the frequency spectrum of its signals should be confined to a low frequency band to abide by the automobile EMI regulations. Some prior art uses a low pass filter to filter the signals and thereby limits its frequency spectrum to a low frequency band for complying with the concerned regulations. However, to the automobile network communication device, such frequency spectrum confinement also means a loss to signal transmission distance and throughput. Therefore, how to prevent the loss under the request of EMI regulations is a serious subject for those working in this field.